<Emphasis Type="Italic">Trichoderma harzianum</Emphasis>: occurrence in the air and clinical significance

Trichoderma harzianum, a filamentous fungus, is being widely used as a potential biopesticide. The potential of this fungus in causing skin sensitization, however, was poorly investigated as yet. The objective of this study was to monitor the occurrence of T. harzianum in the air and to explore its skin sensitizing potential. Seasonal periodicity of T. harzianum was studied for the years 2002–2004 by an Andersen air sampler. The skin sensitizing potential of T. harzianum extract was studied in 389 patients with suspected respiratory allergy by skin prick test (SPT) and specific IgE level was determined by ELISA. SDS–PAGE and immunoblotting were also performed. T. harzianum colony count varied from 3.69 to 134.88 CFU m⁻³ with the peak achieved in February. Relative humidity was found to be a significant (P < 0.05) factor predicting the occurrence of T. harzianum in the air. Positive skin reaction (wheal diameter ≥ 3 mm) was observed in 105 patients (26.99%). T. harzianum crude extract was resolved in 18 protein bands (12–72 kDa) on SDS–PAGE (12% gel) including two IgE-binding protein bands (21 and 32 kDa). T. harzianum can be considered an important inhalant allergen.     

Aeromycoflora of an agricultural farm in West Bengal,India: A five-year study (1994–1999)

A five-year (1994–1999) continuous survey of aeromycoflora had been carried out in an agricultural farm at a suburban area of Greater Calcutta. The sampling was carried out with Burkard volumetric spore trap placed 0.5?meter above the ground level at the centre in a small plot in a rice field. A total of 26 fungal spore types were identified microscopically. The most abundant types were Basidiospores (21.85–5.59%) followed by Cladosporium, Periconia, Nigrospora, Aspergilli group, Ascospores. The seasonal periodicity of the major dominant types had maxima in autumn, during the month of October. This coincided with the harvesting period of the rice crop during rainy season. In Petri plate exposure of nutrient media, different species of aspergilli group, Alternaria, Cladosporium, Curvularia, Nigrospora, and other taxa were identified. The diurnal periodicities recorded for different types were classified into night-time, post dawn, middle day and double maxima (showing two peaks in a day) patterns. In general, no significant correlation between the total air spora and the meteorological parameters could be established. It is evident that the local cropping practices may have some regulating role on spore concentration in the air of the study area.     

Comparative aerobiology,allergenicity and biochemistry of three palm pollen grains in Calcutta,India

A Burkard volumetric trap was used at Salt Lake City, Calcutta, to record the occurrence and frequency of three common palm pollen, namely,Areca catechu, Borassus flabellifer andPhoenix sylvestris for two consecutive years (July 1988–June 1990). The meteorological factors responsible for the frequency of relevant airborne pollen grains were analysed. The allergenic potential of these pollen types was investigated by skin-prick tests on adult respiratory allergic patients. These were also chemically analysed in terms of total carbohydrate, lipid and soluble protein. Total soluble protein of the above types was used in 11% SDS-polyacrylamide gel electrophoresis to study the range of molecular components.     

Aerobiological, clinical and immunobiochemical studies on Lantana camara pollen and cross-reactivity with other Verbenaceae pollen species

Airborne pollen is an important and potent source of aeroallergens. The aim of the study was to conduct a 2-year aerobiological survey in Calcutta, India, for knowing the concentration and seasonal periodicity of Lantana camara (LC) pollen. The sensitization due to this pollen among seasonal respiratory allergic patients and its chemical composition was studied. An aerobiological survey was conducted with a volumetric Burkard sampler from 2004 to 2006. Protein components of LC pollen were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis and IgE immunoblotting. Allergenic activities were determined by in vivo (skin prick test) and in vitro (enzyme-linked immunosorbent assay. In vitro inhibition tests were performed to evaluate cross-reactivity. LC pollen was present from March to May and from September to December contributing up to 10.5% to the total aeropollen load during peak month. Horizontal profile showed highest concentration for nearest (0.5 m) rotorod and it was decreased by half in a distance within 4.5–6.5 m from plot edge. LC pollen contained 7.5% carbohydrate, 19.3% lipid with proline and valine as dominant amino acid. Among 1,500 adult respiratory allergic patients tested, 7.93% showed higher level of positive reaction. IgE binding proteins of 22, 42, 45 and 95 kD were revealed. LC pollen showed remarkable cross-reactivity with other local Verbenaceae pollen taxa (Clerodendron viscosum, Tectona grandis and Vitex negundo). This is the first study on LC pollen regarding its aerobiological, clinical and immuno-biochemical aspects; it should be helpful for the diagnosis and therapy of patients susceptible to LC pollen.     

Incidence of allergenically significant fungal aerosol in a rural bakery of West Bengal,India

The frequency of fungal spores in the air of three different sections of a rural bakery was analyzed using a Burkard personal slide sampler and Andersen two stage viable sampler. In average concentration of spores (No./m³) was 228–26770/m³ and concentration of viable colony forming units (CFU/m³) was 65-2061 CFU/m³. Dominant fungus species both culturable and nonculturable, were species of Aspergillus and Penicillium, Cladosporiumsp., Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Cladosporium cladosporioides, Penicillium citrinum and Alternaria alternata. Seasonal variations in the spore concentrations were clearly observed in case of some fungi. Total culturable mould concentration of different bakery sections sometimes exceeded the acceptable limit for a healthy indoor environment. Antigenic extracts prepared from some dominant culturable fungi showed high level of allergenicity in skin prick tests indicating that they could be responsible for allergic respiratory dysfunction of bakery workers.This revised version was published online in October 2005 with corrections to the Cover Date.     

Prevalence of allergenic pollen grains in the aerosol of the city of Calcutta,India: a two year study

The role of pollen grains as a causative agent of respiratory allergic disorders such as asthma and allergic rhinitis is common and very well established. The aim of this study was to assess the frequencies of airborne pollen in the Calcutta metropolis and to identify the taxa which cause significant amounts of sensitization. An aeropalynological survey of the atmosphere of Calcutta was carried out from 2004 to 2006. Skin tests were performed with a panel of the most common pollen types on local patients with clinical features of pollinosis. The meteorological factors responsible for the frequency of the pollen types were analysed. The results of monthly visits to the clinic by these patients were correlated with the monthly pollen counts of three dominant and perennial pollen taxa. The dominant pollen types were Trema (19%), Poaceae (12.98%), Casuarina (5.76%), Cocos (5.7%), Azadirachta (4.65%), Peltophorum (3.71%), Cyperaceae (3.68%), Delonix (3.18%) and Areca (2.56%). Total pollen concentration seems to have a significant positive correlation with temperature and wind speed whereas there was a negative correlation with humidity. Skin tests were most frequently found to be positive with the pollen of Poaceae (49%), Azadirachta (46%), Cocos (47%), Cyperaceae (35%), Peltophorum (33%), Areca (29%), Phoenix (26%), and Borassus (23%). A positive correlation occurred between visits to the clinic and monthly pollen count of Areca, Cocos, and Poaceae. This is the first study to design a pollen calendar for Calcutta city; it will provide useful data for enabling allergologists to achieve accurate diagnosis for patients with pollen hypersensitivity.     

Airborne pollen of Borassus flabellifer: Quantification of allergen and antigen

Airborne pollen grains of Borassus flabellifer were recorded at Madhyamgram, during February to June 1995–1996 commensurate with the plants flowering season. The following year (1996–1997), the exposed Burkard tape segments with the optimal and minimal daily concentrations were divided into two longitudinal equal halves. For each segment, after immunoblotting, one half was incubated with human sera having high IgE titer against Borassus, and the other half with anti-Borassus rabbit sera for the detection of allergen and antigen respectively. Antigen detection was performed by general immunoblotting method, whereas the allergens were detected by chemiluminescence. The occurrence of the pollen grains in air was compared and correlated with that of the allergen and antigen. The number of allergen and antigen spots were always found to be higher than airborne pollen with great size variation due to the presence of exine free protein particles originating from the pollen grains. The number of allergen spots was always lower than the antigen spots. The occurrence of pollen grains and antigen spots showed stronger positive correlation compared with allergen spots. The peak hours for the occurrence of pollen grains, allergens and antigens were recorded. It is evident from this study that the application of direct aeroallergen monitoring method will be highly useful in allergological research.     

Homology modeling of allergenic cyclophilins: IgE-binding site and structural basis of cross-reactivity

Cross-reactivity among allergens is of considerable scientific as well as clinical interest. Proteins belonging to the allergenic cyclophilin family share a high degree of sequence homology and are cross-reactive. Until date no three-dimensional structural information is available on these proteins and the shared structural features of the epitopes which are the most important determinants of cross-reactivity. Cyclophilins are also known to bind with the immuno-suppressive drug cyclosporin. Comparative molecular modeling of these allergenic cyclophilin proteins of different sources was performed in order to investigate the structural basis of their cross-reactivity. All the proteins studied revealed a similarity in the shape of the cross-reactive epitopes with varying degrees of accessibility. Cyclosporin binding and allergenic properties of these proteins were also found to be structurally related.